Scientometric and Bibliometric Analysis in Analytical Marketing Research

Theoretical background: Analytical marketing is at the heart of scientific research because it plays an important role in building the competitiveness of enterprises and is an opportunity for them to grow.Purpose of the article: The aim of the article is to present the results of a bibliometric analysis of the developing area of analytical marketing.Research methods: For this purpose, specialist journals published between 1900 and 2021 were searched in the Web of Science database. The scientometric analyses carried out on their basis concern the number of publications, authorship and co-authorship, the number of citations, journals, thematic categories, institutions, countries and keywords. Over 200 publications cited 2,563 times were analyzed.Main findings: The concept of analytical marketing was taken into account by over 400 authors, with Maria Petrescu authoring the highest number of publications, and Michel Wedel being the most significant author due to the number of citations. An important role, due to the number of publications in this area, is played by institutions based in the USA (over 50%), including the University of Nevada, Las Vegas (UNLV) and the Nevada System of Higher Education (NSHE). What is more, the conducted research emphasizes the importance of marketing analytics and presents benefits that stem from using it

Time-dependent Effects in Photospheric-Phase Type II Supernova Spectra

Spectroscopic modeling of Type II supernovae (SNe) generally assumes steady-state. Following the recent suggestion of Utrobin & Chugai, but using the 1D non-LTE line-blanketed model atmosphere code CMFGEN, we investigate the effects of including time-dependent terms that appear in the statistical and radiative equilibrium equations. We base our discussion on the ejecta properties and the spectroscopic signatures obtained from time-dependent simulations, investigating different ejecta configurations, and covering their evolution from one day to six weeks after shock breakout. Compared to equivalent steady-state models, our time-dependent models produce SN ejecta that are systematically over-ionized, affecting helium at one week after explosion, but ultimately affecting all ions after a few weeks. While the continuum remains essentially unchanged, time-dependence effects on observed spectral lines are large. At the recombination epoch, HI lines and NaID are considerably stronger and broader than in equivalent steady-state models, while CaII8500A is weakened. If time dependence is allowed for, the HeI lines at 5875A and 10830A appear about 3 times stronger at one week, and HeI10830A persists as a blue-shifted absorption feature even at 6 weeks after explosion. Time dependence operates through the energy gain from changes in ionization and excitation, and, perhaps more universally across SN types, from the competition between recombination and expansion, which in-turn, can be affected by optical-depth effects. Our time-dependent models compare well with observations of the low-luminosity low-velocity SN 1999br and the more standard SN 1999em, reproducing the Halpha line strength at the recombination epoch, and without the need for setting unphysical requirements on the magnitude of nickel mixing.Comment: 19 pages, 18 figures, accepted for publication in MNRAS, high-resolution of the paper at http://hermes.as.arizona.edu/~luc/pap_ddt/pap_ddt.ps.g

Neutrino Signal of Electron-Capture Supernovae from Core Collapse to Cooling

An 8.8 solar mass electron-capture supernova (SN) was simulated in spherical symmetry consistently from collapse through explosion to nearly complete deleptonization of the forming neutron star. The evolution time of about 9 s is short because of nucleon-nucleon correlations in the neutrino opacities. After a brief phase of accretion-enhanced luminosities (~200 ms), luminosity equipartition among all species becomes almost perfect and the spectra of electron antineutrinos and muon/tau antineutrinos very similar. We discuss consequences for the neutrino-driven wind as a nucleosynthesis site and for flavor oscillations of SN neutrinos.Comment: 4 pages, 4 eps figures; published as Physical Review Letters, vol. 104, Issue 25, id. 25110

Spatial distribution of radionuclides in 3D models of SN 1987A and Cas A

Fostered by the possibilities of multi-dimensional computational modeling, in particular the advent of three-dimensional (3D) simulations, our understanding of the neutrino-driven explosion mechanism of core-collapse supernovae (SNe) has experienced remarkable progress over the past decade. First self-consistent, first-principle models have shown successful explosions in 3D, and even failed cases may be cured by moderate changes of the microphysics inside the neutron star (NS), better grid resolution, or more detailed progenitor conditions at the onset of core collapse, in particular large-scale perturbations in the convective Si and O burning shells. 3D simulations have also achieved to follow neutrino-driven explosions continuously from the initiation of the blast wave, through the shock breakout from the progenitor surface, into the radioactively powered evolution of the SN, and towards the free expansion phase of the emerging remnant. Here we present results from such simulations, which form the basis for direct comparisons with observations of SNe and SN remnants in order to derive constraints on the still disputed explosion mechanism. It is shown that predictions based on hydrodynamic instabilities and mixing processes associated with neutrino-driven explosions yield good agreement with measured NS kicks, light-curve properties of SN 1987A, and asymmetries of iron and 44Ti distributions observed in SN 1987A and Cassiopeia A.Comment: 9 pages, 6 figures; submitted to: "SN 1987A, 30 years later", Proceedings IAU Symposium No. 331, 2017; eds. M. Renaud et a

2D Multi-Angle, Multi-Group Neutrino Radiation-Hydrodynamic Simulations of Postbounce Supernova Cores

We perform axisymmetric (2D) multi-angle, multi-group neutrino radiation-hydrodynamic calculations of the postbounce phase of core-collapse supernovae using a genuinely 2D discrete-ordinate (S_n) method. We follow the long-term postbounce evolution of the cores of one nonrotating and one rapidly-rotating 20-solar-mass stellar model for ~400 milliseconds from 160 ms to ~550 ms after bounce. We present a multi-D analysis of the multi-angle neutrino radiation fields and compare in detail with counterpart simulations carried out in the 2D multi-group flux-limited diffusion (MGFLD) approximation to neutrino transport. We find that 2D multi-angle transport is superior in capturing the global and local radiation-field variations associated with rotation-induced and SASI-induced aspherical hydrodynamic configurations. In the rotating model, multi-angle transport predicts much larger asymptotic neutrino flux asymmetries with pole to equator ratios of up to ~2.5, while MGFLD tends to sphericize the radiation fields already in the optically semi-transparent postshock regions. Along the poles, the multi-angle calculation predicts a dramatic enhancement of the neutrino heating by up to a factor of 3, which alters the postbounce evolution and results in greater polar shock radii and an earlier onset of the initially rotationally weakened SASI. In the nonrotating model, differences between multi-angle and MGFLD calculations remain small at early times when the postshock region does not depart significantly from spherical symmetry. At later times, however, the growing SASI leads to large-scale asymmetries and the multi-angle calculation predicts up to 30% higher average integral neutrino energy deposition rates than MGFLD.Comment: 20 pages, 21 figures. Minor revisions. Accepted for publication in ApJ. A version with high-resolution figures may be obtained from http://www.stellarcollapse.org/papers/Ott_et_al2008_multi_angle.pd

Palladium and silver abundances in stars with [Fe/H] > -2.6

Palladium (Pd) and silver (Ag) are the key elements for probing the weak component in the rapid neutron-capture process (r-process) of stellar nucleosynthesis. We performed a detailed analysis of the high-resolution and high signal-to-noise ratio near-UV spectra from the archive of HIRES on the Keck telescope, UVES on the VLT, and HDS on the Subaru Telescope, to determine the Pd and Ag abundances of 95 stars. This sample covers a wide metallicity range with -2.6 $\lesssim$ [Fe/H] $\lesssim$ +0.1, and most of them are dwarfs. The plane-parallel LTE MAFAGS-OS model atmosphere was adopted, and the spectral synthesis method was used to derive the Pd and Ag abundances from Pd I {\lambda} 3404 {\AA} and Ag I {\lambda} 3280/3382 {\AA} lines. We found that both elements are enhanced in metal-poor stars, and their ratios to iron show flat trends at -0.6 < [Fe/H] < +0.1. The abundance ratios of [Ag/H] and [Pd/H] are well correlated over the whole abundance range. This implies that Pd and Ag have similar formation mechanisms during the Galactic evolution.Comment: 15 pages, 12 figures, accepted to A&

Resolution Study for Three-dimensional Supernova Simulations with the Prometheus-Vertex Code

We present a carefully designed, systematic study of the angular resolution dependence of simulations with the Prometheus-Vertex neutrino-hydrodynamics code. Employing a simplified neutrino heating-cooling scheme in the Prometheus hydrodynamics module allows us to sample the angular resolution between 4 degrees and 0.5 degrees. With a newly-implemented static mesh refinement (SMR) technique on the Yin-Yang grid, the angular coordinates can be refined in concentric shells, compensating for the diverging structure of the spherical grid. In contrast to previous studies with Prometheus and other codes, we find that higher angular resolution and therefore lower numerical viscosity provides more favorable explosion conditions and faster shock expansion. We discuss the possible reasons for the discrepant results. The overall dynamics seem to converge at a resolution of about 1 degree. Applying the SMR setup to marginally exploding progenitors is disadvantageous for the shock expansion, however, because kinetic energy of downflows is dissipated to internal energy at resolution interfaces, leading to a loss of turbulent pressure support and a steeper temperature gradient. We also present a way to estimate the numerical viscosity on grounds of the measured turbulent kinetic-energy spectrum, leading to smaller values that are better compatible with the flow behavior witnessed in our simulations than results following calculations in previous literature. Interestingly, the numerical Reynolds numbers in the turbulent, neutrino-heated postshock layer (some 10 to several 100) are in the ballpark of expected neutrino-drag effects on the relevant length scales in the turbulent postshock layer. We provide a formal derivation and quantitative assessment of the neutrino drag terms in an appendix.Comment: 37 pages, 14 figures, 4 tables; revised version with neutrino drag discussion extended for numerical evaluation; accepted by Ap

Three-Dimensional Core-Collapse Supernova Simulations with Multi-Dimensional Neutrino Transport Compared to the Ray-by-Ray-plus Approximation

Self-consistent, time-dependent supernova (SN) simulations in three spatial dimensions (3D) are conducted with the Aenus-Alcar code, comparing, for the first time, calculations with fully multi-dimensional (FMD) neutrino transport and the ray-by-ray-plus (RbR+) approximation, both based on a two-moment solver with algebraic M1 closure. We find good agreement between 3D results with FMD and RbR+ transport for both tested grid resolutions in the cases of a 20 solar-mass progenitor, which does not explode with the employed simplified set of neutrino opacities, and of an exploding 9 solar-mass model. This is in stark contrast to corresponding axisymmetric (2D) simulations, which confirm previous claims that the RbR+ approximation can foster explosions in 2D in particular in models with powerful axial sloshing of the stalled shock due to the standing accretion shock instability (SASI). However, while local and instantaneous variations of neutrino fluxes and heating rates can still be considerably higher with RbR+ transport in 3D, the time-averaged quantities are very similar to FMD results because of the absence of a fixed, artificial symmetry axis that channels the flow. Therefore, except for stochastic fluctuations, the neutrino signals and the post-bounce evolution of 3D simulations with FMD and RbR+ transport are also very similar, in particular for our calculations with the better grid resolution. Higher spatial resolution has clearly a more important impact than the differences by the two transport treatments. Our results back up the use of the RbR+ approximation for neutrino transport in 3D SN modeling.Comment: 25 pages, 16 figures; referee comments included, new appendix added; accepted by Ap

Parallelized Solution Method of the Three-dimensional Gravitational Potential on the Yin-Yang Grid

We present a new method for solving the three-dimensional gravitational potential of a density field on the Yin-Yang grid. Our algorithm is based on a multipole decomposition and completely symmetric with respect to the two Yin-Yang grid patches. It is particularly efficient on distributed-memory machines with a large number of compute tasks, because the amount of data being explicitly communicated is minimized. All operations are performed on the original grid without the need for interpolating data onto an auxiliary spherical mesh.Comment: 8 pages, 4 figures; two minor additions after refereeing; accepted by Ap